The car brakes sharply, blocking the wheels. If the coefficient of friction between the tires and the road is 0.5
| May 26, 2021 | education
The car brakes sharply, blocking the wheels. If the coefficient of friction between the tires and the road is 0.5 and the distance traveled by the car to a stop is 40 meters, then what speed did the car have before braking?
To find the speed of the presented car before braking, we use the equality: μ * m * g = Ffr (friction force) = m * a = m * Vn ^ 2 / 2S, whence we express: Vn = √ (2S * μ * g).
Constants and variables: S – the path of the presented car to the stop (S = 40 m); μ – coefficient. friction between tires and road (μ = 0.5); g – acceleration due to gravity (g ≈ 10 m / s2).
Calculation: Vн = √ (2S * μ * g) = √ (2 * 40 * 0.5 * 10) = 20 m / s.
Answer: Before braking, the presented vehicle had a speed of 20 m / s.
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